Soil is the product of the complex interplay of several factors. Weathering, a process that breaks down rocks by physical (mechanical) or chemical means, is key to soil formation. The source of the weathered mineral matter from which soils develop is called the parent material and is a major factor influencing newly forming soil. Gradually this weathered matter undergoes physical and chemical changes as soil formation progresses. Parent material can either be the underlying bedrock (solid rock) or a layer of loose deposits. When the parent material is bedrock, the soils are termed residual soils, while soils developed on loose materials such as sand or gravel are called transported soils. It should be pointed out that transported soils form in place on parent materials that have been carried from elsewhere and deposited by gravity, water, wind, or ice. Parent material influences soils in two ways. First, the type of parent material influences the rate of weathering and thus the rate of soil formation. Also, because loose deposits are already partly weathered, soil development on such material will likely progress more rapidly than when bedrock is the parent material. Second, the chemical makeup of the parent material will affect the soil’s fertility. This influences the character of the natural vegetation the soil can support. At one time, the parent material was thought to be the primary factor causing differences among soils. However, soil scientists have come to understand that other factors, especially climate, are more important. In fact, similar soils often develop from different parent materials, and dissimilar soils can develop from the same parent material. Such discoveries reinforce the importance of other soil-forming factors.
Climate is considered to be the most influential control of soil formation. Temperature and precipitation are the elements that exert the strongest impact. Variations in temperature and precipitation determine whether chemical or mechanical weathering will predominate and also greatly influence the rate and depth of weathering. For instance, a hot, wet climate may produce a thick layer of chemically weathered soil in the same amount of time that a cold, dry climate produces a thin mantle of mechanically weathered debris. Also, the amount of precipitation influences the degree to which various materials are removed from the soil as water runs through it, thereby affecting soil fertility. Finally, climatic conditions are an important control on the types and numbers of plant and animal life present.
Plants and animals play a vital role in soil formation. The types and abundance of organisms strongly influence the physical and chemical properties of a soil. In fact, for well- developed soils in many regions, the significance of natural vegetation on soil type is frequently implied in the names used by soil scientists, such as prairie soil, forest soil, and tundra soil. Plants and animals furnish organic matter to the soil. Certain bog (swamp) soils are composed almost entirely of organic matter, whereas desert soils might contain as little as a small fraction of 1 percent. Although the quantity of organic matter varies substantially among soils, it is a rare soil that completely lacks it. The primary source of organic matter in soil is plants, although animals and an infinite number of microorganisms also contribute. Decomposed organic matter supplies important nutrients to plants, as well as to animals and microorganisms living in the soil. Consequently, soil fertility is in part related to the amount of organic matter present.
Furthermore, the decay of plant and animal remains causes the formation of various organic acids. These complex acids hasten the weathering process. Organic matter also has a high water-holding ability and thus aids water retention in a soil. Microorganisms, including fungi, bacteria, and single- celled protozoa, play an active role in the decay of plant and animal remains. The end product is humus, a material that no longer resembles the plants and animals from which it is formed. In addition, certain microorganisms aid soil fertility by converting atmospheric nitrogen into soil nitrogen. Earthworms and other tunneling animals mix the mineral and organic portions of a soil. Earthworms, for example, feed on organic matter and thoroughly mix soils in which they live, often moving and enriching many tons per acre each year. Tunnels and holes also aid the passage of water and air through the soil.
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Soil is the product of the complex interplay of several factors. Weathering, a process that breaks down rocks by physical (mechanical) or chemical means, is key to soil formation. The source of the weathered mineral matter from which soils develop is called the parent material and is a major factor influencing newly forming soil. Gradually this weathered matter undergoes physical and chemical changes as soil formation progresses. Parent material can either be the underlying bedrock (solid rock) or a layer of loose deposits. When the parent material is bedrock, the soils are termed residual soils, while soils developed on loose materials such as sand or gravel are called transported soils. It should be pointed out that transported soils form in place on parent materials that have been carried from elsewhere and deposited by gravity, water, wind, or ice. Parent material influences soils in two ways. First, the type of parent material influences the rate of weathering and thus the rate of soil formation. Also, because loose deposits are already partly weathered, soil development on such material will likely progress more rapidly than when bedrock is the parent material. Second, the chemical makeup of the parent material will affect the soil’s fertility. This influences the character of the natural vegetation the soil can support. At one time, the parent material was thought to be the primary factor causing differences among soils. However, soil scientists have come to understand that other factors, especially climate, are more important. In fact, similar soils often develop from different parent materials, and dissimilar soils can develop from the same parent material. Such discoveries reinforce the importance of other soil-forming factors.
Paragraph 1 suggests which of the following about the formation of residual soils?
Inference Questions推理题
AThey have undergone physical but not chemical changes during their formation
BThey form from soils that are less fertile than transported soils.
CTheir formation occurs in a different location than where their parent material was formed.
DThey take longer to form than transported soils do
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Soil is the product of the complex interplay of several factors. Weathering, a process that breaks down rocks by physical (mechanical) or chemical means, is key to soil formation. The source of the weathered mineral matter from which soils develop is called the parent material and is a major factor influencing newly forming soil. Gradually this weathered matter undergoes physical and chemical changes as soil formation progresses. Parent material can either be the underlying bedrock (solid rock) or a layer of loose deposits. When the parent material is bedrock, the soils are termed residual soils, while soils developed on loose materials such as sand or gravel are called transported soils. It should be pointed out that transported soils form in place on parent materials that have been carried from elsewhere and deposited by gravity, water, wind, or ice. Parent material influences soils in two ways. First, the type of parent material influences the rate of weathering and thus the rate of soil formation. Also, because loose deposits are already partly weathered, soil development on such material will likely progress more rapidly than when bedrock is the parent material. Second, the chemical makeup of the parent material will affect the soil’s fertility. This influences the character of the natural vegetation the soil can support. At one time, the parent material was thought to be the primary factor causing differences among soils. However, soil scientists have come to understand that other factors, especially climate, are more important. In fact, similar soils often develop from different parent materials, and dissimilar soils can develop from the same parent material. Such discoveries reinforce the importance of other soil-forming factors.
According to paragraph 1, the parent material affects all of the following aspects of the soil EXCEPT:
Negative Factual Information Questions否定事实信息题
AHow quickly the soil is formed
BHow fertile the soil is
CWhat kinds of vegetation are able to grow in the soil
DWhether or not climate influences soil formation
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Soil is the product of the complex interplay of several factors. Weathering, a process that breaks down rocks by physical (mechanical) or chemical means, is key to soil formation. The source of the weathered mineral matter from which soils develop is called the parent material and is a major factor influencing newly forming soil. Gradually this weathered matter undergoes physical and chemical changes as soil formation progresses. Parent material can either be the underlying bedrock (solid rock) or a layer of loose deposits. When the parent material is bedrock, the soils are termed residual soils, while soils developed on loose materials such as sand or gravel are called transported soils. It should be pointed out that transported soils form in place on parent materials that have been carried from elsewhere and deposited by gravity, water, wind, or ice. Parent material influences soils in two ways. First, the type of parent material influences the rate of weathering and thus the rate of soil formation. Also, because loose deposits are already partly weathered, soil development on such material will likely progress more rapidly than when bedrock is the parent material. Second, the chemical makeup of the parent material will affect the soil’s fertility. This influences the character of the natural vegetation the soil can support. At one time, the parent material was thought to be the primary factor causing differences among soils. However, soil scientists have come to understand that other factors, especially climate, are more important. In fact, similar soils often develop from different parent materials, and dissimilar soils can develop from the same parent material. Such discoveries reinforce the importance of other soil-forming factors.
According to paragraph 1, scientists’ understanding of soil formation has changed in which of the following ways?
Factual Information Questions事实信息题
AResidual soils and transported soils have more similarities than scientists used to believe.
BSoils that scientists used to consider similar are actually very different.
CParent material is a less important factor in soil variation than scientists used to believe.
DDifferences among parent materials are caused by climate differences more often than scientists used to believe.
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Climate is considered to be the most influential control of soil formation. Temperature and precipitation are the elements that exert the strongest impact. Variations in temperature and precipitation determine whether chemical or mechanical weathering will predominate and also greatly influence the rate and depth of weathering. For instance, a hot, wet climate may produce a thick layer of chemically weathered soil in the same amount of time that a cold, dry climate produces a thin mantle of mechanically weathered debris. Also, the amount of precipitation influences the degree to which various materials are removed from the soil as water runs through it, thereby affecting soil fertility. Finally, climatic conditions are an important control on the types and numbers of plant and animal life present.
According to paragraph 2, a hot, wet climate may have which of the following effects on soil formation as compared to a cold, dry climate?
Factual Information Questions事实信息题
AIncreased rates of mechanical weathering
BHigher levels of chemical weathering
CA thinner soil layer
DSlower removal of various materials that affect soil fertility from the soil
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Plants and animals play a vital role in soil formation. The types and abundance of organisms strongly influence the physical and chemical properties of a soil. In fact, for well- developed soils in many regions, the significance of natural vegetation on soil type is frequently implied in the names used by soil scientists, such as prairie soil, forest soil, and tundra soil. Plants and animals furnish organic matter to the soil. Certain bog (swamp) soils are composed almost entirely of organic matter, whereas desert soils might contain as little as a small fraction of 1 percent. Although the quantity of organic matter varies substantially among soils, it is a rare soil that completely lacks it. The primary source of organic matter in soil is plants, although animals and an infinite number of microorganisms also contribute. Decomposed organic matter supplies important nutrients to plants, as well as to animals and microorganisms living in the soil. Consequently, soil fertility is in part related to the amount of organic matter present.
The word “substantially” in the passage is closest in meaning to
Vocabulary Questions词汇题
AOccasionally
BNaturally
CSignificantly
DUnpredictably
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Plants and animals play a vital role in soil formation. The types and abundance of organisms strongly influence the physical and chemical properties of a soil. In fact, for well- developed soils in many regions, the significance of natural vegetation on soil type is frequently implied in the names used by soil scientists, such as prairie soil, forest soil, and tundra soil. Plants and animals furnish organic matter to the soil. Certain bog (swamp) soils are composed almost entirely of organic matter, whereas desert soils might contain as little as a small fraction of 1 percent. Although the quantity of organic matter varies substantially among soils, it is a rare soil that completely lacks it. The primary source of organic matter in soil is plants, although animals and an infinite number of microorganisms also contribute. Decomposed organic matter supplies important nutrients to plants, as well as to animals and microorganisms living in the soil. Consequently, soil fertility is in part related to the amount of organic matter present.
In paragraph 3, what is the author’s purpose in listing the names of some types of soil?
Factual Information Questions事实信息题
ATo suggest that natural vegetation has a more significant effect on soil type than animal life does
BTo emphasize the point that natural vegetation strongly influences properties of the soil
CTo identify regions where soils are well developed
DTo show how soil scientists discovered that plants furnish organic matter to certain types of soil
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Furthermore, the decay of plant and animal remains causes the formation of various organic acids. These complex acids hasten the weathering process. Organic matter also has a high water-holding ability and thus aids water retention in a soil. Microorganisms, including fungi, bacteria, and single- celled protozoa, play an active role in the decay of plant and animal remains. The end product is humus, a material that no longer resembles the plants and animals from which it is formed. In addition, certain microorganisms aid soil fertility by converting atmospheric nitrogen into soil nitrogen. Earthworms and other tunneling animals mix the mineral and organic portions of a soil. Earthworms, for example, feed on organic matter and thoroughly mix soils in which they live, often moving and enriching many tons per acre each year. Tunnels and holes also aid the passage of water and air through the soil.
According to paragraph 4, the decay of plant and animal remains affects the soil in which TWO of the following ways? To receive credit, you must select TWO answer choices.
Factual Information Questions事实信息题
Select 2 answers
AIt reduces the amount of acid in the soil.
BIt makes the weathering process faster.
CIt leads to the formation of humus.
DIt reduces soil mixing.
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Furthermore, the decay of plant and animal remains causes the formation of various organic acids. These complex acids hasten the weathering process. Organic matter also has a high water-holding ability and thus aids water retention in a soil. Microorganisms, including fungi, bacteria, and single- celled protozoa, play an active role in the decay of plant and animal remains. The end product is humus, a material that no longer resembles the plants and animals from which it is formed. In addition, certain microorganisms aid soil fertility by converting atmospheric nitrogen into soil nitrogen. Earthworms and other tunneling animals mix the mineral and organic portions of a soil. Earthworms, for example, feed on organic matter and thoroughly mix soils in which they live, often moving and enriching many tons per acre each year. Tunnels and holes also aid the passage of water and air through the soil.
According to paragraph 4, earthworms have which of the following effects on soil?
Factual Information Questions事实信息题
AThey add to the nitrogen content of the soil.
BThey feed on microorganisms that make the soil more fertile.
CThey remove organic matter from the mineral portion of the soil.
DThey help water and air move through the soil.
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Plants and animals play a vital role in soil formation. The types and abundance of organisms strongly influence the physical and chemical properties of a soil. In fact, for well- developed soils in many regions, the significance of natural vegetation on soil type is frequently implied in the names used by soil scientists, such as prairie soil, forest soil, and tundra soil. [■]Plants and animals furnish organic matter to the soil. [■]Certain bog (swamp) soils are composed almost entirely of organic matter, whereas desert soils might contain as little as a small fraction of 1 percent. [■]Although the quantity of organic matter varies substantially among soils, it is a rare soil that completely lacks it. [■]The primary source of organic matter in soil is plants, although animals and an infinite number of microorganisms also contribute. Decomposed organic matter supplies important nutrients to plants, as well as to animals and microorganisms living in the soil. Consequently, soil fertility is in part related to the amount of organic matter present.
Look at the four squares [■]that indicate where the following sentence could be added to the passage
As a result, environments in which more organisms are present usually have soils that are richer in organic matter.Insert Text Questions句子插入题
Where would the sentence best fit？Click on a square sentence to the passage.
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Soil formation involves various factors.
Prose Summary Questions概要小结题
Select 3 answers
AThe soil formation process and some properties of the soil depend partly on whether the soil originates from underlying bedrock or loose materials like sand and gravel
BA long weathering process removes some types of organic matter from the soil, making the soil layer thinner and the soil less fertile.
CSome types of plants take in large amounts of nutrients from the soil and reduce its fertility, allowing fewer other organisms to survive in the soil.
DTemperature and precipitation affect soil formation both directly and by influencing the variety and abundance of living organisms that are important for soil formation
EDecomposed organic matter contributes to soil formation, and the behaviors of microorganisms and some animals support soil fertility.
FA balance between the mineral and chemical portions of the soil is vital for the soil’s ability to support living organisms, especially microorganisms.
